What are "_" and ".." in C#?

Question

Dear All,

What are "_" and ".." in C#?

Answer 1

Hi @BenTam-3003 , Welcome to Microsoft Q&A,

In C#, "_" and ".." are not special symbols or operators with specific meanings. However, they may be used in some contexts based on developer convention or naming preferences.

Underscore (_) in C#:

• In C#, the underscore (_) is a valid character in variable and identifier names. It is often used as a prefix or suffix to indicate private fields or variables within a class. For example:

  csharpCopy code
  private int _myPrivateVariable;
  

Here, _myPrivateVariable is a private variable, and the underscore is a naming convention to signify that it is intended for internal use within the class.

Double Dot (..) in C#:

• In C#, the double dot (..) is not a standard operator or symbol. However, it might be used in certain contexts, such as in the System.Range type introduced in C# 8.0. The range operator .. is used to create a range of values. For example:

  csharpCopy code
  int[] numbers = { 0, 1, 2, 3, 4, 5 };
var subArray = numbers[1..4]; // Creates a range from index 1 to 3 (inclusive)
  

In this example, numbers[1..4] creates a sub-array that includes elements at indices 1, 2, and 3 from the numbers array.

Best Regards,

Jiale

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". 

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

Hey BenTam Thats a great question and thanks for posting it on QandA platform "" in C#: In C#, "" is used as a variable name when you don't intend to use the variable. It's like a placeholder to indicate that the value is being ignored. For example:

var (_, _, result) = SomeMethod(); // Ignoring the first two values

".. in C#: In C#, ".." doesn't have any special meaning. It's not a recognized operator or syntax. If you've encountered it in a specific context, it might be part of a custom implementation or a specific library.

If this helps kindly accept the answer thank much.